Poly(vinyl butyral) (PVB) is commonly used in the manufacture of polymer layers that can be used as interlayers in light-transmitting laminates such as safety glass or polymeric laminates. Safety glass often refers to a transparent laminate comprising a plasticized poly(vinyl butyral) interlayer disposed between two sheets of glass. Safety glass often is used to provide a transparent barrier in architectural and automotive openings. Its main function is to absorb energy, such as that caused by a blow from an object, without allowing penetration through the opening or the dispersion of shards of glass, thus minimizing damage or injury to the objects or persons within an enclosed area. Safety glass also can be used to provide other beneficial effects, such as to attenuate acoustic noise, reduce UV and/or IR light transmission, and/or enhance the appearance and aesthetic appeal of window openings.
Interlayers often comprise, in addition to their polymeric component, various agents that function to alter the spectrum of radiation that is transmitted through the finished glazing product. Those agents, however, often are unstable or cause undesirable effects in a finished laminate.
What are needed in the art are interlayers that are formulated in a manner so that desirable agents are stably maintained without impacting other characteristics of the polymer interlayer.